All nice enough choices.
I would go with
Elisabeth - well,
Elizabeth really.
My Spanish teacher frequently refers to his daughter
Elizabeth as
Isabel, I think that
Elizabeth with the occasional pet name of
Isabella could work.
Elisabeth is a lot more timeless - I mean I know popularity doesn't matter to you and I can understand that, but if they were both number 10 I would go with
Elizabeth because it is more connected to the English language? I guess? And a name American women have been consistently named for hundreds of years, and English speaking women hundreds and hundreds of years before that? Not that I think there is anything wrong with going outside of your own language, of course, but I think there is something very powerful about being connected to your own language and therefore to the rich heritage of your female ancestors for hundreds of years...
of course if you're not english-speaking all of this would apply to
Isabella! I really hope I don't come across the wrong way, my top combo being
Minerva Maria Cecilia and all. Both are lovely but I'd go with
Elizabeth.
ELISABETH! (I def. prefer the Z though I feel it is
MUCH more sensible.)